These are the money-makers: World's 10 biggest healthcare companies by revenue

McKesson Corp. is the world's largest healthcare company by revenue, followed by UnitedHealth Group and CVS Health, according to Verdict Medical Devices.

Here are biggest healthcare companies based on 2017 revenues:

1. McKesson Corp. (San Francisco) – $208.3 billion

McKesson posted a year-over-year revenue growth of 4.9 percent in 2017. The growth is believed to stem from price increases, higher drug utilization, business acquisitions and strong relationships with pharmaceutical distribution business customers in North America.

Anthem's revenue increase of 5.8 percent year-o ver-year was driven by revenue growth across all of its segments. Its commercial and specialty business revenue grew 5.3 percent, and government business revenue grew 6.2 percent.

Aetna's revenue declined by 4 percent in 2017 from $63.1 billion in 2016. The drop was due to lower premiums, temporary suspension of the health insurer fee and the sale of its group insurance segment for $1.45 billion.

10. Humana (Louisville, Ky.) – $53.7 billion

Lower revenue from Humana's individual commercial segment caused its overall 2017 revenues to decrease by 1 percent year over year. Total premiums and services revenues also dropped 1 percent from the year prior to $53.36 billion.